Issue description

This CL undoes a longstanding hack where we artificially remove support for proprietary codecs on all non-android bots
In CL https://chromium-review.googlesource.com/c/chromium/src/+/849641
This allows bots with proprietary codecs to gain some coverage, but creates the unfortunate situation where we have mismatched expectations between bots with codecs vs bots without. To workaround this mismatch, the following tests are marked pass|fail:
external/wpt/html/semantics/embedded-content/media-elements/mime-types/canPlayType.html
external/wpt/media-source/mediasource-addsourcebuffer.html
external/wpt/media-source/mediasource-buffered.html
external/wpt/media-source/mediasource-config-change-mp4-a-bitrate.html
external/wpt/media-source/mediasource-config-change-mp4-av-audio-bitrate.html
external/wpt/media-source/mediasource-config-change-mp4-av-framesize.html
external/wpt/media-source/mediasource-config-change-mp4-av-video-bitrate.html
external/wpt/media-source/mediasource-config-change-mp4-v-bitrate.html
external/wpt/media-source/mediasource-config-change-mp4-v-framerate.html
external/wpt/media-source/mediasource-config-change-mp4-v-framesize.html
external/wpt/media-source/mediasource-endofstream.html
external/wpt/media-source/mediasource-is-type-supported.html
external/wpt/media-source/mediasource-sequencemode-append-buffer.html
external/wpt/media-source/mediasource-sourcebuffer-mode-timestamps.html
Tests marked pass|fail are still not allowed to crash or timeout, so we do gain some benefit from running these.
This bug serves to document the pass|fail TextExpectation and tracks any future work to improve the situation. Ideas considered include
1) Custom expecatations (like we do for Msan bots) for bots with codecs vs those without
2) Running tests requiring codecs as chrome browser_tests, and skipping as LayoutTests.
Jrummell@ is exploring option 2 here:
https://chromium-review.googlesource.com/c/chromium/src/+/792347
Assigning to him to update with the results of that effort.